There are many factors effect performance, such as Hardware, OS, Database system, Application system.

For database factors, there are also many factors. Performance is decided by these factors. Memory Allocation is only one of them.

To achieve the best performance, please consider all these factors.

It is important to ensure there is enough physical memory to prevent the operating system from swapping the DCCA to disk too often or it will seriously degrade the performance.

Please refer to the following aspects to change setting:

1. Page buffer size --- should depend on hit ratio to adjust.
2. Journal file size and journal buffer --- if the system has long transactions, need to set big a little.
3. SCA--- the more DB_LetPT and DB_LetRP setting, the more SCA. Because there are more lock records in SCA.
4. Mainly adjust page buffer size, but not SCA.
5. In addition, need to leave some free memory.

Performance Tuning should combine run situation of the real system. After the first setting, user should continually monitor the Database, and then turn.